Lithium-Ion Battery Energy Density

Author:Source:Datetime: 2016-10-27 16:11:54

Energy density, is the unit volume or weight can be stored in the number of energy, this indicator is, of course, the higher the better, all concentrated are the best thing. Charge and discharge rate is the energy storage and release speed, preferably seconds, and instantly full or release, called the play that is to go.

Of course, these are ideal, in fact, subject to a variety of practical factors, we can not get unlimited energy, it is impossible to achieve the instantaneous transfer of energy. How to constantly break through these restrictions, to achieve a higher level, that is, we need to solve the problem.

It can be said that the current density of energy-intensive lithium-ion battery development is the biggest bottleneck. Whether cell phones, or electric vehicles,solar powered portable generator, people are looking to the battery's energy density to reach a new level, making the product's battery life or mileage is no longer a major factor in troubled products.

From the lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and then to lithium-ion batteries, energy density has been constantly upgrading. But the speed of improvement relative to the pace of industrial-scale development, relative to the human demand for energy level, it is too slow.

Some people even joke, the progress of mankind have been stuck in the "battery" here. Of course, if one day to achieve global power wireless transmission, where "wireless" access to electricity (like cell phone signal), then the human will no longer need the battery, and social development will naturally not stuck in the battery above.

Aiming at the bottleneck of energy density, countries around the world have formulated relevant policy objectives of the battery industry, expect to lead the battery industry in the energy density achieved significant breakthrough. For example when use lifepo4 battery pack in solar system. China, the United States, Japan and other countries or industry organizations to develop the 2020 target, basically point to 300Wh / kg this value, equivalent to the current basis to enhance close to 1 times. 2030 long-term goal, to reach 500Wh / kg, or even 700Wh / kg, the battery industry must have a major breakthrough in the chemical system, can achieve this goal.

There are many factors that affect the energy density of lithium-ion batteries, lithium-ion battery on the existing chemical system and structure, the specific which have obvious limitations?

In front of our analysis, as the power carrier, in fact, the battery which is the lithium element, like in lifepo4 batteries, other substances are "waste", but to obtain stable, sustained, safe electric carrier, these "waste" is indispensable . For example, a lithium-ion batteries, the proportion of the quality of lithium elements in general is also a little more than 1%, the remaining 99% of the ingredients are not bear the energy storage function of other substances. Edison has a famous saying, success is 99% of the sweat plus 1% of the talent, it seems that the universally applicable ah, 1% is safflower, the remaining 99% is the green leaves, which are not less.

So to improve the energy density, we first think of is to increase the proportion of lithium elements, while allowing as many lithium ions from the positive run out, move to the negative, and then have to return from the negative number of positive cathode (not less) , The cycle of carrying energy.